<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>

<script src="../js/vue.js"></script>
<div id="app">

  <h2 v-if="isShow">
    <div>123</div>
    <div>123</div>
    <div>123</div>
    <div>123</div>
    <div>123</div>
    <h2 v-else>isShow为false的时候显示这个</h2>
  </h2>
  {{message}}
</div>

<script>
  const app = new Vue({
    el: '#app',
    data: {
      message: "第一次，系统的学VUE",
      isShow:true
    }
  })
</script>
</body>
</html>